220 THE AMERICAN NATURALIST [Vol.XLVII 



are more advanced at one end than at the other and the 

 maturation processes are at a similar stage in the differ- 

 ent sacs of the same anther. Cursory examination of re- 

 duction phenomena in the ovule confirmed these observa- 

 tions. 



Many anthers of the abnormal (300-309) when ex- 

 amined cytolqgically, were entirely normal in all their 

 phases of maturation. Others showed evidences of al- 

 most total sterility through premature breaking down 

 of the archesporial tissue, while still others were only 

 partially sterile. Anthers of this strain were mentioned 

 earlier as sometimes having more than four pollen sacs. 

 In such cases the maturation phases were in very dif- 

 ferent stages in the different sacs. In one sac the arche- 

 sporium might be in early prophase, while in other com- 

 partments there would be almost mature pollen. This 

 extreme variation in maturation was not confined to 

 anthers with an abnormal sac number, but was often true 

 of those normal in this respect. Conditions in the 

 anthers of the abnormal strain are similar as regards 

 the normal cytological phenomena, but various abnor- 

 malities are not uncommon. These manifest themselves 

 in such a manner that one can not avoid believing that 

 some subtle agent is at work here, too, distorting the in- 

 ternal as well as the larger so-called external characters. 

 In both reduction divisions in all the strains examined, 

 various abnormal phenomena are to be found which are 

 not due to fixation or other technical operations. Con- 

 trasted with the normal (402) the maturation phases in 

 different sacs of the same anther may be far apart. 

 Nearly mature pollen is present in some sacs, while 

 others in the same anther may not have progressed 

 farther than diakinesis. Pollen tetrads are often rare 

 in nearly mature anthers. This is true of at least five 

 per cent, of those examined. Mother-cells may break 

 down during early prophase, diakinesis or any of the 

 later phases. In early prophase, the nuclear membrane 

 may disappear and the whole archesporium disintegrate. 



